The present invention relates to a device and a method for controlling vehicle interior lighting, in which a plurality of lighting-relevant vehicle states each determined by at least one state condition that can be interrogated, is monitored and if the existence of one of the vehicle states is detected, a corresponding control process to turn the interior lighting on or off is activated.
A vehicle interior lighting is known from German Patent Document 36 20 861 A1 which monitors the position of the vehicle doors as a vehicle state relevant to illumination, and turns on the interior lighting when a door is opened and turns it off on a time-delayed basis when the door is closed, by gradually extinguishing the bulb. The time-delayed shutoff means that the vehicle occupants, even in darkness, can readily perform the actions required to begin driving, for example putting on the safety belt, inserting the ignition key, etc. by means of the interior lighting which is still active. A similar procedure in which the lighting is initially reduced by a certain amount when the door is closed, then remains constant, and finally is dimmed linearly, is disclosed in U.S. Pat. No. 4,866,345.
German Patent Document 33 09 548 C2 describes a vehicle interior lighting control in which a vehicle state is monitored that is governed by two conditions, namely an open or closed vehicle door and the ignition being off or on. When closing of the door is detected, the interior lighting is turned off with a time delay. This also takes place when an open door and an "off" ignition are detected, preventing unnecessary activation of the interior illumination if the vehicle door is accidently left open, while when the door is open and the ignition is on, the interior lighting remains activated.
In an interior lighting system according to German Patent Document 41 31 425 A1, an entry light, a foot area light, and a seat light on the vehicle ceiling are provided which, when opening of the corresponding vehicle door is detected, are switched on in the direction of entry with a brightness that increases from light to light, producing an increase in brightness from the road and the door sill across the floor to the seat.
An object of the present invention is to provide a method and a device for controlling the vehicle interior lighting that has a comfortable vehicle interior lighting control that is optimally adapted to the respective situation, with simultaneously low construction cost.
This and other objects are achieved by the present invention which provides a method for controlling vehicle interior lighting, comprising the steps of: determining each of a plurality of lighting-relevant vehicle states by interrogating at least one state condition that can be interrogated; monitoring the vehicle states and if one of the vehicle states is detected, activating a corresponding control process to turn the interior lighting on or off; wherein the corresponding control processes to turn the interior lighting on or off include respective dimming processes, and includes setting dimming parameters which determine the dimming processes, said dimming parameters being set as a function of the vehicle state that is detected and that activates the corresponding control process.
The objects are also achieved by a device constructed in accordance with the present invention and comprises: a central lighting control unit with a program memory containing a program pattern of the method of the invention; a sensor group coupled to the central lighting control unit, the sensor group interrogating the state conditions for the lighting-relevant vehicle states, and producing output signals that are fed to the central lighting control unit; a lighting device coupled to the central lighting control unit; and a switch coupled between the central lighting control unit and the lighting device, and is controllable by the central lighting control unit for activating and deactivating the lighting device.
The method of the invention takes into account not only one vehicle state, characterized for example by the opening or closing of a vehicle door, but several such lighting-relevant vehicle states established by one or more state conditions that can be interrogated, for example the state of the ignition, central locking, and a glow plug preheater as well as the position of the ignition key. With presettable dimming parameters adjusted to the detected vehicle state, the method then activates a dimming process to turn on or turn off the vehicle interior lighting, with the dimming process being adjustable in a highly variable fashion to the current situation. Provision of a central lighting control unit for the plurality of control functions of the method, whose pattern is stored in a program memory, and by which the controllable switch is controlled, entails only low construction cost.
In certain embodiments of the invention, a lighting-relevant vehicle state includes a chain of several state conditions, which must all be present before lighting control activation takes place. For example, a vehicle state of this kind can consist of the linked conditions of an ignition in the "on" position, an open vehicle door, and the undershooting of a certain boundary value for the measured vehicle interior brightness. Such an improvement makes it possible, when a certain state condition exists, for example an open vehicle door, for different lighting activities to be performed nonetheless as a function of other interrogated state conditions.
Certain embodiments of the invention allow the possibility of turning off the interior lighting depending on the situation, at different rates by a suitable choice of a corresponding shutoff dimming time. In addition, with certain other embodiments, a delay in the start of dimming that depends upon the vehicle state can be achieved for switching off the illumination.
In certain preferred embodiments, for controlled switching-on of the interior lighting as a function of the state of the vehicle, the situation-dependent setting of the turning-on dimming time as well as the resultant final brightness are provided as dimming parameters.
In certain embodiments of the invention, the illumination-relevant vehicle states are ranked so that if a vehicle higher-priority state exists, the corresponding interior lighting control process is activated, for example after interruption of a corresponding control process for a vehicle state of lower priority.
Embodiments of the invention provide that, as a condition inherent to each of the lighting-relevant vehicle states, an interrogation is performed to determine whether the measured vehicle interior brightness is below a preselected limit. This is intended to prevent the vehicle interior lighting being activated unnecessarily in daylight, if another state condition of the respective lighting-relevant vehicle state, for example opening or closing a door, is fulfilled.
Certain embodiments allow the use of vehicle interior brightness as a state condition for the control process that can be interrogated, preferably in the form of a digital, especially a two-valued, bright/dark signal.
The use of only a single connecting lead both for controlling the lighting device and for transmitting the brightness sensor signal in certain embodiments keeps the construction cost low, and also reduces the number of leads that have to be run in the vehicle.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.